Isolement et caractérisation des bactéries à potentiel favorisant la croissance des plantes, associée à quelques plantes spontanées sahariennes

Abstract

In the present study, 77 bacteria were isolated from the roots of five spontaneous Saharan plants indigenous to the Ghardaïa region. The isolates were screened for their ability to fix atmospheric nitrogen and to solubilise inorganic phosphate and potassium. Macroscopic and microscopic identification as well as biochemical tests of the isolates revealed the dominance of the following genera: Bacillus and Pseudomonas. All isolates were tested for their ability to promote germination and growth of barley seeds in vitro. From this test, isolates (MF2, MF5, MF4, LK4, MF10, LK1, LK5, US1, US9 and US8) expressed interesting PGP abilities and were tested for their efficacy in improving germination and growth of barley (Hordeum vulgare L.) and tomato (Solanum lycopersicum) seeds. Germination rates, seedling and root lengths and fresh and dry weights were registered. Overall observation of the results revealed an improvement in seedling growth under in vitro conditions compared with the control. These results suggest that rhizospheric bacteria from natural plants in arid habitats constitute an interesting source for the isolation of bacteria with PGP potential that can be used to improve the growth of cultivated plants.